Toy building blocks for constructing repeating geometric structures from identical blocks are known. For example the well known cube sets widely used as toys comprise a plurality of identical cubes which can be stacked side by side or on top of one another. More complex building modules are also known such as the module shown in U.S. Pat. No. 3,950,888 to Hogan; U.S. Pat. No. 4,492,723 to Chadwick, II; and U.S. Pat. No. 3,659,360 to Zeischegg. All of these known construction sets have a disadvantage in that they can not be stacked to form complex structures without using special connecting means such as pins for inserting into holes. All of the known construction sets further have the disadvantage of limited possibilities for assembling complex bodies.